Insulin sensitivity and blood pressure in a biethnic sample: The Miami community health study

Abstract

An association between blood pressure and insulin sensitivity among normotensive African, Americans has not been demonstrated consistently in epidemiologic studies. Part of the discrepancy may be due to studying persons with profound obesity—an insulin-resistant state itself. The association between insulin-mediated glucose uptake (i.e., insulin sensitivity) and blood pressure was examined among 25 nondiabetic African-American and 28 white non-Hispanic persons aged 25–44 years who ranged from normal weight to obese, using the hyperinsulinemic euglycemic clamp technique. In bivariate analyses, insulin sensitivity was inversely related to systolic ( p < 0.01) and diastolic blood pressure ( p = 0.08) among African- American persons and to diastolic blood pressure among white non-Hispanic subjects ( p < 0.05). Covariate adjustment for age and sex had only a marginal effect on these results. When the data were pooled and further adjusted for ethnicity, insulin sensitivity remained significantly associated with both systolic and diastolic blood pressure (p < 0.01 for each). To consider the effect of obesity, body mass index (BMI) was divided at the sample median (26.5 kg/m') and the analyses were repeated within each stratum. Among those whose BMI was below the median value, each increment in insulin sensitivity was associated with a 2-mmHg decrease in systolic blood pressure (p = 0.02). These results suggest that ethnicity was not a strong effect modifier in this sample and indicated that insulin sensitivity was inversely related to blood pressure level in these normotensive African-American and white, non-Hispanic participants.